Simplify the following expression: $z = \dfrac{6}{5k + 5} \div \dfrac{6}{3k}$
Dividing by an expression is the same as multiplying by its inverse. $z = \dfrac{6}{5k + 5} \times \dfrac{3k}{6}$ When multiplying fractions, we multiply the numerators and the denominators. $z = \dfrac{ 6 \times 3k } { (5k + 5) \times 6}$ $z = \dfrac{18k}{30k + 30}$ Simplify: $z = \dfrac{3k}{5k + 5}$